1. Field of the Invention
The present invention relates generally to surround sound processors and more specifically to a two channel audio surround sound circuit with automatic level control, which is less complicated than that of the prior art.
2. Discussion of the Prior Art
Surround sound processors are normally used to decode surround sound audio signals, which are recorded on the sound tracks of video cassettes and discs. Surround sound processors will also enhance the imaging of audio recordings. However, these surround sound processors use complicated circuitry to create a three dimensional sound field using as many as five speakers. The five speakers create a three dimensional sound field similar to that found in a modern movie theater.
U.S. Pat. No. 4,495,637 to Bruney discloses an apparatus and method for enhanced psychoacoustic imagery using asymmetric cross-channel feed. The Bruney patent includes asymmetric bi-directional audio signal cross-feed established between first and second audio sign processing channels. U.S. Pat. No. 4,748,669 to Klayman discloses a stereo enhancement system. The Klayman patent includes a stereo enhancement system which provides an enhanced wider stereo image and a wider listening area, and further provides perspective correction for achieving correct stereo sound perspective with speakers at different locations and with headphones.
U.S. Pat. No. 5,420,929 to Geddes et al. discloses a signal processor for sound image enhancement. The Geddes et al. patent includes providing fluctuating coherence between the left channel and right channel outputs by crossfeeding a high pass portion of the left channel to the right output and like portion of the right channel to the left output. U.S. Pat. No. 5,434,921 to Dombrowski, Jr. et al. discloses a stereo image control circuit. The Dombrowski, Jr. patent includes a stereo circuit which ranges between a mono mode through a stereo mode to a wide mode.
Patent application no. 2006/0215848 to Ambourn discloses a simplified amplifier providing sharing of music with enhanced spatial presence through multiple headphone jacks. The Ambourn patent includes a personal listening device used in connection with the amplification of signals for enhancing the perceived quality and ambiance of sound heard by a listener using stereo headphones or small speakers.
Accordingly, there is a clearly felt need in the art for a two channel audio surround sound circuit with automatic level control, which provides improved imaging and has a less complicated design than that of the prior art.